1. Field of the Invention
The present invention relates to an input device (touch panel) used in conjunction with a liquid crystal display (LCD) and the like, and to a method for manufacturing the input device.
2. Description of the Related Art
For example, as described in Japanese Unexamined Patent Application Publication No. 2009-301767, a touch panel includes a transparent surface panel (transparent substrate 23), a decorative layer (light-shielding layer 24) formed in a decorative region under the surface panel, a transparent planarizing layer (overcoat layer 25) formed over the entire undersurface of the surface panel and decorative layer, and a transparent electrode (transparent conductive layer 26) formed on the undersurface of the planarizing layer.
In the touch panel described in Japanese Unexamined Patent Application Publication No. 2009-301767, the planarizing layer is formed by spin-coating a transparent resin, such as a photosensitive acrylic resin.
However, when the planarizing layer is a resin layer formed by spin coating, the degree of planarization of the planarizing layer is reduced particularly due to, for example, a level difference between the surface panel and the decorative layer. As a result, since the transparent electrode cannot be formed on a planarized surface, the sensor sensitivity may be reduced.
While Japanese Unexamined Patent Application Publication No. 2009-301767 does not specifically describe a method for manufacturing an input device, the method involves a manufacturing process in which a decorative layer, a planarizing layer, and a transparent electrode are stacked on each of surface panels obtained by dividing a glass panel. This may lead to lower productivity and cause variations in quality among touch panels.
Moreover, if a roll-to-roll method is adopted in the manufacturing process, it is not possible to use glass for the surface panel in the configuration described in Japanese Unexamined Patent Application Publication No. 2009-301767. Even if glass is used, there are restrictions on the properties of the glass. For better contact with the decorative layer or for later division into separate pieces, such glass as tempered glass cannot be used.
A touch panel described in Japanese Unexamined Patent Application Publication No. 2009-193587 is also formed by staking a decorative layer (masking layer 12) in a decorative region under a surface panel (single substrate 11), a planarizing layer (smooth layer 15), and a transparent electrode (sense circuit 13), and thus suffers from problems similar to those of the touch panel described in Japanese Unexamined Patent Application Publication No. 2009-301767.
The present invention has been made to solve the problems of the related art described above. The present invention provides a low-profile input device that has high sensor sensitivity and can be manufactured by roll-to-roll processing, and also provides a method for manufacturing the input device.